Color stabilization of propargyl alcohol



United States Patent 3,285,974 Patented Nov'. 15, 1966 pargyl alcohol todistillation at 85 to 100 mm. pressure 3,235,974 to obtain an acid freeand water white alcohol. COLOR STABILIZATION 0F PROPARGYL Theprerequisite amount of either acid may be added Haluk Senmm g% assign)!to General directly to the freshly distilled propargyl alcohol at roomAniline & Film Corporatio n, New York, N.Y., a cor- 5 tempeiature with i1d lgeslrad one part porafion of Delaware by weight of the acid may bemixed with two to two and No Drawing. Filed 05. 15, 1963, Ser. No.316,438 one half parts y Weisiht of distilled Water, the aqueous 3Claims. (Cl. 260-6325) solution allowed to cool, and then diluted withfreshly distilled propargyl alcohol to yield a solution containing Thisinvention relates to a process of stabilizing proany desiredconcentration. Such solution then may be pargyl alcohol againstdiscoloration. added at room temperature to the freshly distilled pro-Propargyl alcohol, after preparation in the reaction of pargyl alcoholwith agitation. acetylene with formaldehyde followed by distillation ofIn order to demonstrate the effectiveness of the presence the crudeproduct in the conventional manner, develops of either sulfuric orphosphoric acid in the propargyl upon standing a color ranging fromyellow to dark brown, alcohol against discoloration, the followingprocedure was depending on the length of time of storage at normaltemresorted to: perature. Freshly distilled propargyl alcohol has an al-An 0.5% solution of 95% strength of sulfuric acid in most water whitecolor. A yellowish color usually defreshly distilled propargyl alcoholwas prepared by weighvelops within a few days following distillation.The ing out in a glass vessel one gram of distilled water to color ishighly objectionable where the propargy l alcohol which was added /2gram of 95% sulfuric acid followed is to be used as an intermediate inthe preparation of y fiafeful IIliXing- The aqueous Sulfuric acid Was ofsulfa'diazine, plasticizers and specialty chemicals. lowed to cool, andto it were added 98 ml. of freshly dis- It is an object of the presentinvention to provide a tilled propargyl alcohol and thoroughly mixed.This process of stabilizing propangyl alcohol against discolorasolutionwas kept in an ice bath until used. tion by treatment thereof withsulfuric or phosphoric An 0.5% solution of phosphoric acid in freshlydistilled acid. proparigyl alcohol was prepared as above with the ex-Other objects and advantages will become apparent cep i n t -6 g am of82% phosphoric acid was used from the following description: instead of0.5 gram of sulfuric acid.

I have found that freshly distilled propargyl alcohol, Freshlydistlllfid P P EY filwhol Samples were meashaving a b i paint f about115 C, and ifi ured and placed in carefully cleaned two ounce screw topgravity at 25/4 C. of 0.95, can be very readily stabilized Q whichmeasured amounts of acid were added against discoloration upon storageat normal temperature Wlthy surfing The treated Sampks were then placedon by the addition thereto of from 50 to 1,000 parts of eitherlaborttory Shelf at l temperature P days sulfuric acid of 95 to 99%strength or phosphoric acid of g a detinmnedd i VCS a i Color 80 to 85%strength per million parts of alcohol. The f i Sea i 2 A 71 days acidcontaining propargyl alcohol resists discoloration 6 C001. 0 e Samp es iadam etermmg durin stonoe For Iona 1S 4 to 6 months The r S The samplesproducts having a VCS color of less than th P e i one are considered aswater white. VCS values of one p e sma quan I er m t e g to two areslightly yellowish and the yellowish color proalco ol 1s not at alldetrimental when used as an inter- 40 gressively deepening to a VCSvalue of Beyond 5, medlate l aforemfintloned P If P the color becomesprogressively b rowner and at 18 the once of acid 1n the propargylalcohol should lnterfere color is a deep dd b 1n the use of the alcoholas an intermediate 1n ohernic-al The results of the foregoing procedureare shown i synthesis, 1t 1s very sunple to. SllbJBCt the stabilizedprothe following table:

a Composition Ml. of 0.5% Sample No. of Sample m1. Sulfuric Acid Cone.40 days at 71 da s at of Propargyl in Propargyl of Acid, .T. VCS R.l.VCS

alcohol Alcohol p.p.m.

Ml. of 0.5% Phosphoric Acid in Propargyl Alcohol On the 72nd day, SampleNos. 1 to 8 inclusive were placed in an oven at 95100 C. for 33 hours, acolor reading taken, and the samples allowed to remain in the oven foran additional 83 hours followed by a color reading. The results obtainedwere as follows:

95-100 0. Sample No.

33 hours 116 hours No references cited.

LEON ZITVER, Primary Examiner.

J. E. EVANS, Assistant Examiner.

1. PROPARGYL ALCOHOL CONTAINING UNIFORMLY DISPERSED THEREIN FROM FIFTYTO ONE THOUSAND PARTS OF AN ACID SELECTED FROM THE CLASS CONSISTING OFSULFURIC AND PHOSPHORIC ACID PER ONE MILLION PARTS OF PROPAGYL ALCOHOL.